CN112744215B

CN112744215B - System and method for avoiding rear cross traffic collisions

Info

Publication number: CN112744215B
Application number: CN202011197187.0A
Authority: CN
Inventors: 姜恩奭
Original assignee: Hyundai Mobis Co Ltd
Current assignee: Hyundai Mobis Co Ltd
Priority date: 2019-10-31
Filing date: 2020-10-30
Publication date: 2023-12-05
Anticipated expiration: 2040-10-30
Also published as: US11192499B2; DE102020128484A1; CN112744215A; KR20210051872A; US20210129749A1

Abstract

A system and method for avoiding rear cross traffic collisions, the system comprising: an obstacle detection unit that detects a position of an obstacle by receiving electromagnetic waves reflected from a reflection point of the obstacle; a direction estimating unit that estimates a traveling direction of the obstacle based on the position of the obstacle detected by the obstacle detecting unit; and a collision determination unit that determines a possibility of collision with the obstacle based on the traveling direction of the obstacle estimated by the direction estimation unit. In accordance with the present disclosure, the system and method of avoiding rear cross traffic collisions solves the problem of erroneously determining that a vehicle is likely to collide with an obstacle moving in a direction parallel to the vehicle.

Description

System and method for avoiding rear cross traffic collisions

Technical Field

The present inventive concept relates to a system and method for avoiding rear cross traffic collisions. More particularly, the present inventive concept relates to a system and method of detecting an obstacle whose traveling direction intersects with a traveling direction of a vehicle when the vehicle is parked or reversed, and alerting a driver of the obstacle.

Background

With the development of advanced technologies related to automatic driving of vehicles, various vehicle safety technologies have been developed in consideration of convenience and safety of drivers. These safety techniques have been applied to actual vehicles.

In particular, techniques for determining the possibility of a collision between a particular vehicle and another vehicle or obstacle and thus warning the driver of the particular vehicle or controlling the particular vehicle have been developed. Among these technologies, a Rear cross traffic collision warning (rcaw) function is a function of identifying an obstacle approaching from the side and warning the driver when the vehicle is parked or backed up.

However, the rear cross traffic collision warning function recognizes an obstacle approaching a specific vehicle by using a radar. Therefore, there is a problem in that the position of the reflection point on the obstacle identified by the radar through reflection may vary according to the distance to the specific vehicle.

Therefore, in the related art, when the reflection point on the obstacle that gives back reflection to the radar moves, it is erroneously recognized that the obstacle traveling parallel to the specific vehicle will collide with the specific vehicle.

The foregoing is intended only to aid in understanding the background of the disclosure and is not intended to represent that the disclosure falls within the scope of the related art known to those skilled in the art.

Disclosure of Invention

The present disclosure is directed to a system for avoiding rear cross traffic collisions to address the problem of erroneously determining that a vehicle may collide with an obstacle traveling parallel to the longitudinal direction of the vehicle.

Additional features of the inventive concepts will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the inventive concepts.

According to the present disclosure, there is provided a system for avoiding rear cross traffic collisions, the system comprising: an obstacle detection unit that detects a position of an obstacle by receiving electromagnetic waves reflected from a reflection point of the obstacle; a direction estimating unit that estimates a traveling direction of the obstacle based on the position of the obstacle detected by the obstacle detecting unit; and a collision determination unit that determines a possibility of collision with the obstacle based on the traveling direction of the obstacle estimated by the direction estimation unit.

The obstacle detection unit may be connected to a radar sensor provided at each of opposite rear ends of a vehicle, and detect a position of the obstacle located behind or sideways of the vehicle.

The direction estimating unit may collect a plurality of positions of the obstacle detected by the obstacle detecting unit, and calculate a ratio between a change in a longitudinal position of the obstacle and a change in a lateral position of the obstacle using the collected plurality of positions of the obstacle, thereby estimating a traveling direction of the obstacle.

The direction estimating unit may calculate a ratio between a change in the longitudinal position and a change in the lateral position occurring between an initial position of the obstacle detected for the first time and a current position of the obstacle, thereby estimating a traveling direction of the obstacle in real time.

The collision determination unit determines that there is no possibility of collision with the obstacle when the estimated approach angle between the traveling direction of the obstacle and the lateral axis of the vehicle is within a preset angle range.

The obstacle detection unit may calculate a lateral distance from the vehicle to the obstacle or a lateral speed of the obstacle by using the detected position of the obstacle, and the collision determination unit may determine that there is no possibility of collision with the obstacle when a variation in the lateral distance to the obstacle or a variation in the lateral speed of the obstacle is equal to or less than a preset variation.

The system may further include: a reliability evaluation unit that collects a plurality of traveling directions of the obstacle estimated by the direction estimation unit and evaluates an estimated reliability level of the traveling direction of the obstacle by using a variance or a standard deviation between the number of collected traveling directions and the collected traveling directions, wherein the collision determination unit determines a possibility of collision with the obstacle based on the traveling directions of the obstacle when the estimated reliability level estimated by the reliability evaluation unit is equal to or greater than a preset reliability level.

The obstacle detecting unit may calculate a lateral distance from the vehicle to the obstacle and a lateral speed of the obstacle by using the detected position of the obstacle, and the collision determining unit may calculate a collision time based on the calculated lateral distance and the calculated lateral speed, and may determine that there is a possibility of collision with the obstacle when the obstacle is located within a preset area and the collision time is equal to or less than a preset time.

The collision determination unit may set the lateral speed of the obstacle by using the lateral speed of the obstacle detected previously and the lateral speed of the obstacle detected currently, based on the traveling direction of the obstacle.

The collision determination unit may adjust the preset region based on a traveling direction of the obstacle so as to exclude a partial region adjacent to the vehicle from the preset region.

The system may further include a notification providing unit that provides a notification to a driver of the vehicle when it is determined by the collision determining unit that there is a possibility of collision with the obstacle.

According to the present disclosure, there is provided a method of avoiding a rear cross traffic collision, the method comprising: receiving, by a vehicle, electromagnetic waves reflected from a reflection point of an obstacle, and detecting a position of the obstacle; estimating a traveling direction of the obstacle according to the detected position of the obstacle; and determining a possibility of collision with the obstacle according to the detected position of the obstacle or the estimated traveling direction of the obstacle.

In accordance with the present disclosure, the system and method of avoiding rear cross traffic collisions solves the problem of erroneously determining that a vehicle is likely to collide with an obstacle moving in a direction parallel to the vehicle.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the principles of the invention. The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a block diagram illustrating a system for avoiding rear cross traffic collisions according to an embodiment of the present disclosure.

Fig. 2 is a flowchart illustrating a method of avoiding rear cross traffic collisions according to an embodiment of the present disclosure.

Fig. 3 is a diagram showing the reflection points and the main reflection points of the obstacle at a long distance and a short distance from the vehicle when the obstacle and the vehicle travel parallel to each other.

Fig. 4 is a diagram illustrating a preset area according to an embodiment of the present disclosure.

Fig. 5 is a diagram illustrating a method of estimating a traveling direction of an obstacle according to an embodiment of the present disclosure.

Fig. 6 is a graph showing a traveling direction of an obstacle according to a approach angle of the obstacle.

Fig. 7 is a graph illustrating reliability levels according to an embodiment of the present disclosure.

Fig. 8 is a diagram showing a variation in a preset area of an embodiment of the present disclosure.

Detailed Description

Unless otherwise indicated, the illustrative exemplary embodiments should be understood to provide exemplary features of varying detail in some way of practicing the inventive concept. Thus, unless otherwise indicated, features, components, modules, layers, films, panels, regions, and/or aspects, etc. (hereinafter referred to individually or collectively as "elements") of the various embodiments may be combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.

Hatching and/or shading is typically used in the drawings to illustrate the boundaries between adjacent elements. As such, unless otherwise indicated, no particular material, material property, dimension, proportion, commonality between illustrated elements, and/or any other characteristic, property, or the like, is conveyed or indicated whether or not a section line or shadow exists. In addition, in the drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. While the exemplary embodiments may be implemented in different ways, the particular sequence of processes may be performed in a different order than that described. For example, two consecutively described processes may be performed substantially simultaneously or in reverse order from that described. Also, like reference numerals designate like elements.

For the purposes of this disclosure, "at least one of X, Y and Z" and "at least one selected from the group consisting of X, Y and Z" may be interpreted as X only, Y only, Z only, or any combination of two or more of X, Y and Z, such as XYZ, XYY, YZ and ZZ. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Spatially relative terms, such as "under," "below," "beneath," "below," "above," "over," "above," "lateral" (e.g., such as "sidewall") and the like, may be used herein for descriptive purposes to describe one element's relationship to another element as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use, operation and/or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" may include both an orientation above and below. Furthermore, the device may be otherwise oriented (e.g., rotated 90 degrees or in other directions), and thus, the spatially relative descriptors used herein interpreted accordingly.

It should also be noted that as used herein, the terms "generally," "about," and other similar terms are used as approximation terms and not degree terms and, therefore, are used to explain the inherent deviation from measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.

As is common in the art, some exemplary embodiments are described and illustrated in the figures in terms of functional blocks, units, and/or modules. Those skilled in the art will appreciate that the blocks, units, and/or modules are physically implemented by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, hardwired circuits, memory elements, wires, or the like, which may be formed using semiconductor-based manufacturing techniques or other manufacturing techniques. Where blocks, units, and/or modules are implemented by a microprocessor or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform the various functions discussed herein, and may optionally be driven by firmware and/or software. It is also contemplated that each block, unit, and/or module may be implemented with dedicated hardware, or as a combination of dedicated hardware performing certain functions and a processor (e.g., one or more programmed microprocessors and associated circuits) performing other operations. Moreover, each block, unit, and/or module of some example embodiments may be physically separated into two or more interacting and discrete blocks, units, and/or modules without departing from the scope of the inventive concept. Furthermore, blocks, units, and/or modules of some example embodiments may be physically combined into more complex blocks, units, and/or modules without departing from the scope of the inventive concept.

The specific structural and functional descriptions of the embodiments of the inventive concepts described in the specification or the application are for illustrative purposes only of the embodiments of the inventive concepts. Embodiments of the inventive concept may be embodied in many different forms and the embodiments of the present specification or the application should not be construed as limiting the inventive concept.

As embodiments of the present disclosure may be modified in various ways and may have various forms, specific embodiments are shown in the drawings and will be described in detail in the specification or application. However, the embodiments of the concepts according to the inventive concept should not be construed as limited to the specific disclosure, and should be construed as including all modifications, equivalents, or alternatives falling within the spirit and technical scope of the disclosure.

The terms "first," "second," and the like, as used in the specification, may be used to describe various elements, but these elements should not be construed as limited to these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element without departing from the scope of the inventive concept. Similarly, a second element may also be referred to as a first element.

It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element or intervening elements may be present therebetween. In contrast, it will be understood that when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements present. Other words used to describe the relationship between elements such as "between," "directly between," "adjacent," and "directly adjacent" should be interpreted in the same manner.

The terminology used in the description presented herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concepts. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be understood that terms such as "comprises," "comprising," "includes," and the like are intended to indicate the presence of features, numbers, steps, actions, elements, components, or combinations thereof disclosed in the specification, and are not intended to exclude the possibility that one or more other features, numbers, steps, actions, elements, components, or combinations thereof may be present or added.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept pertains. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Hereinafter, exemplary embodiments of the inventive concept will be described in detail with reference to the accompanying drawings. Like reference numerals refer to like elements throughout the drawings.

Fig. 1 is a block diagram illustrating a system 100 for avoiding rear cross traffic collisions according to an embodiment of the inventive concept. Fig. 2 is a flowchart illustrating a method of avoiding a rear cross traffic collision according to an embodiment of the inventive concept.

Referring to fig. 1 and 2, according to an embodiment of the inventive concept, there is provided a system for avoiding a rear cross traffic collision, the system including: an obstacle detection unit 20 that detects the position of the obstacle B by receiving electromagnetic waves reflected from the reflection point of the obstacle B (as shown in fig. 3); a direction estimating unit 30 that estimates a traveling direction of the obstacle B based on the position of the obstacle B detected by the obstacle detecting unit 20; and a collision determination unit 40 that determines a possibility of collision with the obstacle B based on the position of the obstacle B detected by the obstacle detection unit 20 or the traveling direction of the obstacle B estimated by the direction estimation unit 30.

The obstacle detecting unit 20, the direction estimating unit 30, the collision determining unit 40, the reliability estimating unit 50, and the notification providing unit 60 according to the exemplary embodiments of the inventive concept may be implemented by a nonvolatile memory (not shown) configured to store data related to an algorithm configured to control operations of various elements of the vehicle or software instructions configured to reproduce the algorithm, and a processor (not shown) configured to perform operations described below by using the data stored in the memory. Here, the memory and the processor may be implemented as separate chips. In the alternative, the memory and processor may be implemented as an integrated single chip. The processor may be provided in the form of one or more processors.

In addition, according to an embodiment of the inventive concept, there is provided a method of avoiding a rear cross traffic collision, the method including, in operation S100, receiving electromagnetic waves reflected from a reflection point of an obstacle B by a vehicle a, and detecting a position of the obstacle B; in operation S200, estimating a traveling direction of the obstacle B based on the detected position of the obstacle B; in operation S300, the possibility of collision with the obstacle B is determined based on the position of the detected obstacle B or the traveling direction of the obstacle B estimated by the direction estimating unit 30.

The obstacle detection unit 20 detects the position of the obstacle B. The position of the obstacle B may be detected using various sensors such as the radar sensor 10, an ultrasonic sensor, a lidar sensor, and the like. The obstacle detection unit 20 detects the relative position of the obstacle B with respect to the vehicle a, and calculates the distance from the vehicle a to the obstacle B.

The obstacle detection unit 20 detects the position of the obstacle B by transmitting electromagnetic waves and receiving electromagnetic waves reflected from the reflection point of the obstacle B. In particular, a sensor that transmits or receives electromagnetic waves may be provided at the rear end of the vehicle a.

Specifically, the obstacle detection unit 20 is connected to the radar sensor 10 provided at each of opposite rear ends of the vehicle a, and detects the position of the obstacle B located behind or laterally of the vehicle a.

The radar sensor 10 emits electromagnetic waves such as microwaves to the obstacle B and receives the electromagnetic waves reflected from the obstacle B, thereby detecting a distance, a direction, a height, and the like with respect to the obstacle B. The radar sensor 10 is provided at the opposite side of the vehicle a, and may be provided at the rear end of the vehicle a. The detection area of the radar sensor 10 may be an angular range extending from the rear of the vehicle a to the opposite side.

In addition, the obstacle detection unit 20 may detect a plurality of positions of the obstacle B, and may calculate the speed of the obstacle B using the detected position change of the obstacle B. In particular, the obstacle detection unit 20 may separate the distance between the vehicle a and the obstacle B, and separate the speed of the obstacle B into a longitudinal component and a lateral component.

The collision determination unit 40 may determine the possibility of collision between the vehicle a and the obstacle B by using the distance between the vehicle a and the obstacle B calculated based on the position of the obstacle B and the other position of the obstacle B and the speed of the obstacle B.

According to an embodiment of the inventive concept, the collision determination unit 40 may determine the possibility of collision with the obstacle B based on the traveling direction of the obstacle B estimated by the direction estimation unit 30. Specifically, although the possibility of collision may be determined from the distance between the vehicle a and the obstacle B calculated from the position of the obstacle B detected by the obstacle detecting unit 20 and the other position of the obstacle B and the speed of the obstacle B, the collision determining unit 40 may determine that there is no possibility of collision between the vehicle a and the obstacle B in consideration of the traveling direction of the obstacle B estimated by the direction estimating unit 30.

Fig. 3 is a diagram showing the reflection points and the main reflection points of the obstacle B at a longer distance and a shorter distance from the vehicle a when the obstacle B and the vehicle a travel parallel to each other.

As shown in fig. 3, the radar sensor 10 provided at the rear end of the vehicle a can detect the position of the obstacle B located behind and to the side of the vehicle a. The reflection point of the obstacle B may be located at the front and side adjacent to the vehicle a.

Specifically, when the obstacle B is located at a long distance from the rear of the vehicle a, the main reflection point is located at the front of the obstacle B. When the obstacle B is located at a short distance from the vehicle a, the main reflection point is located at the side of the obstacle B. A long distance may be considered when obstacle B is at least one or more vehicle lengths from vehicle a, up to the point where obstacle B passes beyond vehicle a. When obstacle B is overrunning vehicle a and some portion of obstacle B spans vehicle a, it may be considered a short distance.

According to the related art, there are the following problems. When the obstacle B is spaced apart from the vehicle a in the lateral direction and travels parallel to the longitudinal direction of the vehicle a, there is no possibility of collision between the obstacle B and the vehicle a. However, as the main reflection point for the vehicle a moves in the lateral direction, the obstacle B is erroneously determined to travel in the lateral direction.

Here, the longitudinal direction of the vehicle a refers to the overall length direction of the vehicle a. The lateral direction of the vehicle a refers to the full width direction of the vehicle a (as shown in fig. 4). The main reflection point refers to a reflection point detected as being closest to the vehicle a among reflection points of the obstacle B, or refers to a reflection point of an electromagnetic wave having the highest level, from which the reception signal is reflected.

Accordingly, the collision determination unit 40 according to an embodiment of the inventive concept may determine the possibility of collision with the obstacle B based on the traveling direction of the obstacle B estimated by the direction estimation unit 30.

The obstacle detection unit 20 uses the detected position of the obstacle B to calculate the lateral distance from the vehicle a to the obstacle B and the lateral speed of the obstacle B. The collision determination unit 40 calculates a collision time based on the calculated lateral distance and the calculated lateral velocity. When the obstacle B is located within the preset area and the collision time is equal to or less than the preset time, the collision determination unit 40 determines that there is a possibility of collision with the obstacle B.

Specifically, the obstacle detection unit 20 may calculate the distance from the vehicle a to the obstacle B and the speed of the obstacle B based on the position of the obstacle B. In particular, the obstacle detection unit 20 may divide the distance to the obstacle B and the speed of the obstacle B into a longitudinal component and a transverse component by using the distance to the position of the detected obstacle B and the direction thereof.

The collision determination unit 40 calculates a collision time based on the calculated lateral distance and the calculated lateral velocity. When the obstacle B is located within the preset area and the collision time is equal to or less than the preset time, the collision determination unit 40 determines that there is a possibility of collision with the obstacle B.

Fig. 4 is a diagram illustrating a preset area 400 according to an embodiment of the inventive concept.

Fig. 4 shows a preset area 400 for the obstacle B detected by the radar sensor 10 provided at the right rear end of the vehicle a. The different preset area for the obstacle B detected by the radar sensor 10 disposed at the left rear end of the vehicle may be preset to be symmetrical to the above-described preset area.

In addition, the collision determination unit 40 calculates a collision time (time to collision, TTC), and when the calculated collision time is equal to or less than a preset time, the collision determination unit 40 determines that there is a possibility of collision with the obstacle B. As one example, the collision time may be calculated using the following equation.

k-th radar frame

TTC time to collision

In particular, when the obstacle B is located within the preset area and at the same time the collision time is equal to or less than the preset time, the collision determination unit 40 determines that there is a possibility of collision with the obstacle B.

Fig. 5 is a diagram 500 illustrating a method of estimating a traveling direction of an obstacle B according to an embodiment of the inventive concept. Fig. 6 is a graph showing the traveling direction of the obstacle B according to the approach angle of the obstacle B.

Referring to fig. 5 and 6, the direction estimating unit 30 collects a plurality of positions of the obstacle B detected by the obstacle detecting unit 20, and calculates a ratio between a change in the longitudinal position of the obstacle B and a change in the lateral position of the obstacle B using the collected positions of the obstacle B, thereby estimating the traveling direction of the obstacle B.

The obstacle detection unit 20 detects the position of the obstacle B in real time, and thus detects a plurality of positions of the obstacle B. The direction estimating unit 30 calculates the position change of the obstacle B by using the plurality of positions of the obstacle detecting unit 20. As one example, the direction estimation unit 30 may estimate the traveling direction of the obstacle B by using a change between the current position and the previously detected position of the obstacle B.

Specifically, the direction estimating unit 30 calculates a ratio between a change in the longitudinal position and a change in the lateral position occurring between the initial position of the obstacle B detected for the first time and the current position of the obstacle B, thereby estimating the traveling direction of the obstacle B in real time.

Specifically, the approach angle θ of the obstacle B _k The estimation is performed as follows. Here, the approach angle θ of the obstacle B _k Is the angle between the transverse axis of the vehicle a and the direction of travel of the obstacle B.

Since the amount of change from the initial position to the current position of the obstacle B is used, even if the reflection point for identifying the obstacle B changes, the approach angle θ _k Nor does it change significantly. Therefore, the possibility of collision with the obstacle B is not erroneously determined.

As shown in fig. 6, when approaching the angle theta _k Equal to or greater than the first angle, it is determined that the obstacle B is traveling parallel to the vehicle. When approaching angle theta _k And when the angle is smaller than the second angle, determining that the obstacle B runs perpendicular to the vehicle. In addition, when approaching the angle theta _k When the first angle is smaller and equal to or larger than the second angle, it is determined that the obstacle B is diagonally traveling.

When the estimated approach angle theta between the traveling direction of the obstacle B and the lateral axis of the vehicle a _k The collision determination unit 40 determines that there is no possibility of collision with the obstacle B when within the preset angle range. Here, the preset angle range may be preset to be equal to or greater than the first angle and equal to or less than the right angle (90 degree angle).

The preset angle range may be preset to be larger than the approach angle θ caused by the movement of the main reflection point when the obstacle B travels parallel to the vehicle a _k Is a variation of (c). Further, the preset angle range may be preset to be smaller than the approach angle θ in the case where the angle of the obstacle B changes in the vicinity of the vehicle a and the obstacle B may actually collide with the vehicle a _k Is a variation of (c).

Fig. 7 is a graph illustrating reliability levels according to an embodiment of the inventive concept.

Referring to fig. 7, the system further includes a reliability evaluation unit 50, which collects a plurality of traveling directions of the obstacle B estimated by the direction estimation unit 30, and evaluates an estimated reliability level of the traveling direction of the obstacle B by using a variance or standard deviation between the number of collected traveling directions and the collected traveling directions. Further, when the estimated reliability level estimated by the reliability estimation unit 50 is equal to or greater than the preset reliability level, the collision determination unit 40 determines the possibility of collision with the obstacle B based on the traveling direction of the obstacle B.

As shown in fig. 7, the estimated reliability level γ of the traveling direction of the obstacle B _k May be equal to having the number of collected directions of travel and the variance or standard deviation between the collected directions of travel as a function of the variables.

Row of obstacle BThe estimated reliability level of the direction of travel is proportional to the number of collected directions of travel and to the variance or standard deviation sigma between the collected directions of travel _k Inversely proportional.

When the estimated reliability level estimated by the reliability estimation unit 50 is equal to or greater than the preset reliability level, the collision determination unit 40 determines the possibility of collision with the obstacle B based on the traveling direction of the obstacle B.

Specifically, when the estimated reliability level is equal to or greater than the preset reliability level and the approach angle according to the traveling direction of the obstacle B is within the preset angle range, it is determined that there is no possibility of collision with the obstacle B.

As one example, when determining the approach angle θ according to the traveling direction of the obstacle B _k When there is no possibility of collision with the obstacle B within the preset angle range, the collision determination unit 40 immediately determines that there is no possibility of collision.

According to another embodiment, the collision determination unit 40 may set the lateral speed of the obstacle B by using the lateral speed of the previously detected obstacle B and the lateral speed of the currently detected obstacle B based on the obstacle B of the traveling direction.

Specifically, when the collision time calculated using the lateral speed of the obstacle B is within the preset time, the collision determination unit 40 determines that there is a possibility of collision.

Therefore, when determining the approach angle θ according to the traveling direction of the obstacle B _k The collision determination unit 40 sets the lateral velocity of the obstacle B by using the lateral velocity of the previously detected obstacle B and the lateral velocity of the currently detected obstacle B when within the preset angle range. Specifically, the lateral velocity of the obstacle B used to calculate the collision time is corrected as shown in the following equation.

Y _vel ＝α·Y _vel,k +β·Y _vel,k-1

Here, Y _vel,k Is the currently detected lateral velocity, Y _vel,k-1 Is the transverse velocity just previously detected, and α and β are scale factors.

The factors α and β may be preset to satisfy the equation α+β=1.

Fig. 8 is a diagram illustrating a variation in a preset area of an embodiment of the inventive concept.

Referring to fig. 8, the collision determination unit 40 may modify the previous preset area to another preset area 800 to exclude a part of the area adjacent to the vehicle a from the other preset area 800 based on the traveling direction of the obstacle B.

Specifically, when it is determined that the approach angle according to the traveling direction of the obstacle B is within the preset angle range, the previous preset area 400 is modified so as to be smaller than before. In particular, the previous preset area 400 may be modified so as to exclude an area adjacent to the rear of the vehicle a in the longitudinal direction. That is, the previous preset area 400 may be modified to be defined to be spaced a predetermined distance from the vehicle a in the backward direction and to be spaced a predetermined distance in the lateral direction.

Therefore, when the obstacle B travels behind the vehicle a and is located at a short distance from the vehicle a and the main reflection point also moves, it is determined that there is no possibility of collision.

The system further includes a notification providing unit 60, the notification providing unit 60 providing a notification to the driver when it is determined by the collision determining unit 40 that there is a possibility of collision with the obstacle B. The notification providing unit 60 may provide the notification in a visual manner, a tactile manner, a vibration manner, or the like by using a device such as a dashboard, audio, video, and Navigation (AVN), or the like.

The notification providing unit 60 determines whether the vehicle a is in R range (reverse range). The notification providing unit 60 provides a notification to the driver only when the vehicle a is in R range.

As another embodiment, the obstacle detecting unit 20, the direction estimating unit 30, or the collision determining unit 40 determines whether the vehicle a is in R range. Only in the case of R range, obstacle B is detected, the direction is estimated or the possibility of collision is determined.

Although specific embodiments of the present inventive concept have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the disclosed concept as disclosed in the accompanying drawings.

Claims

1. A system for avoiding rear cross traffic collisions, the system comprising:

an obstacle detection unit that detects a position of an obstacle by receiving electromagnetic waves reflected from a reflection point of the obstacle;

a direction estimating unit that estimates a traveling direction of the obstacle based on the position of the obstacle detected by the obstacle detecting unit;

a collision determination unit that determines a possibility of collision with the obstacle based on the traveling direction of the obstacle estimated by the direction estimation unit; and

a reliability evaluation unit that collects a plurality of traveling directions of the obstacle estimated by the direction estimation unit and evaluates an estimated reliability level of the traveling direction of the obstacle by using a variance or standard deviation between the number of collected traveling directions and the collected traveling directions,

wherein the collision determination unit determines a possibility of collision with the obstacle based on a traveling direction of the obstacle when the estimated reliability level estimated by the reliability estimation unit is equal to or greater than a preset reliability level.

2. The system according to claim 1, wherein the obstacle detection unit is connected to a radar sensor provided at each of opposite rear ends of a vehicle, and detects a position of the obstacle located behind or laterally of the vehicle.

3. The system according to claim 1, wherein the direction estimating unit collects a plurality of positions of the obstacle detected by the obstacle detecting unit, and calculates a ratio between a change in a longitudinal position of the obstacle and a change in a lateral position of the obstacle using the collected plurality of positions of the obstacle, thereby estimating a traveling direction of the obstacle.

4. A system according to claim 3, wherein the direction estimating unit calculates a ratio between a change in the longitudinal position and a change in the lateral position occurring between an initial position of the obstacle detected for the first time and a current position of the obstacle, thereby estimating a traveling direction of the obstacle in real time.

5. The system according to claim 1, wherein the collision determination unit determines that there is no possibility of collision with the obstacle when the estimated approach angle between the traveling direction of the obstacle and the lateral axis of the vehicle is within a preset angle range.

6. The system according to claim 5, wherein the obstacle detection unit calculates a lateral distance from the vehicle to the obstacle or a lateral speed of the obstacle by using the detected position of the obstacle, and

the collision determination unit determines that there is no possibility of collision with the obstacle when the amount of change in the lateral distance to the obstacle or the amount of change in the lateral speed of the obstacle is equal to or smaller than a preset amount of change.

7. The system according to claim 1, wherein the obstacle detection unit calculates a lateral distance from a vehicle to the obstacle and a lateral speed of the obstacle by using the detected position of the obstacle, and

the collision determination unit calculates a collision time based on the calculated lateral distance and the calculated lateral velocity, and determines that there is a possibility of collision with the obstacle when the obstacle is located within a preset area and the collision time is equal to or less than a preset time.

8. The system according to claim 7, wherein the collision determination unit sets the lateral speed of the obstacle by using the lateral speed of the obstacle detected previously and the lateral speed of the obstacle detected currently, based on the traveling direction of the obstacle.

9. The system according to claim 7, wherein the collision determination unit adjusts the preset area based on a traveling direction of the obstacle so as to exclude a partial area adjacent to the vehicle from the preset area.

10. The system of claim 1, further comprising:

a notification providing unit that provides a notification to a driver of the vehicle when it is determined by the collision determining unit that there is a possibility of collision with the obstacle.

11. A method of avoiding a rear cross traffic collision, the method comprising:

receiving, by a vehicle, electromagnetic waves reflected from a reflection point of an obstacle, and detecting a position of the obstacle;

estimating a traveling direction of the obstacle according to the detected position of the obstacle;

determining a possibility of collision with the obstacle according to the detected position of the obstacle or the estimated traveling direction of the obstacle; and

collecting a plurality of estimated travel directions of the obstacle, and estimating an estimated reliability level of the travel direction of the obstacle by using a variance or standard deviation between the number of collected travel directions and the collected travel directions,

wherein when the estimated reliability level estimated is equal to or greater than a preset reliability level, a possibility of collision with the obstacle is determined based on a traveling direction of the obstacle.

12. The method according to claim 11, wherein in estimating the traveling direction of the obstacle, a plurality of positions of the detected obstacle are collected, and a ratio between a change in the longitudinal position of the obstacle and a change in the lateral position of the obstacle is calculated using the collected plurality of positions of the obstacle, thereby estimating the traveling direction of the obstacle.

13. The method according to claim 11, wherein in determining the possibility of collision with the obstacle, it is determined that there is no possibility of collision with the obstacle when an estimated approach angle between a traveling direction of the obstacle and a lateral axis of the vehicle is within a preset angle range.

14. The method according to claim 11, wherein, in detecting the position of the obstacle, a lateral distance from the vehicle to the obstacle or a lateral speed of the obstacle is calculated using the detected position of the obstacle, and

when determining a possibility of collision with the obstacle, calculating a collision time from the calculated lateral distance and the calculated lateral speed, and determining that there is a possibility of collision with the obstacle when the obstacle is located within a preset area and the collision time is equal to or less than a preset time.